1. Field
The present disclosure relates to an organic light emitting display device, and more particularly, to an organic light emitting display device with an insulating layer formed as a multi-layered structure.
2. Description of the Related Art
Generally, an organic light emitting display device is a self-emission display device which has an organic light emitting diode that emits light to display an image.
Since the organic light emitting display device does not require a separate light source unlike a liquid crystal display, it is possible to relatively reduce a thickness and a weight of the organic light emitting display device. Further, since the organic light emitting display device has high-quality characteristics such as low power consumption, high luminance, and a high response speed, the organic light emitting display device has received attention as the next-generation display device for portable electronic apparatuses.
In general, the organic light emitting diode includes a hole injection electrode, an organic emission layer, and an electron injection electrode. In the organic light emitting diode, a hole supplied from the hole injection electrode and an electron supplied from the electron injection electrode are coupled with each other in the organic emission layer to form an exciton, and light is generated by energy generated when the exciton falls in a ground state.
The organic light emitting display device is divided into a top emission type organic light emitting display device and a bottom emission type organic light emitting display device according to a direction in which light generated from the organic emission layer is emitted.
In the case of the bottom emission type organic light emitting display device, since self-emission efficiency is not high, an optical cavity layer generating optical resonance may be included in order to improve emission efficiency.
The light generated from the emission layer is repeatedly reflected in the optical cavity layer to cause constructive interference or destructive interference. That is, light having a predetermined wavelength is amplified and light having other wavelengths is offset, and as a result, only the light having the predetermined wavelength selectively passes through the optical cavity layer. Accordingly, emission efficiency, luminance, and color purity of the organic light emitting display device including the optical cavity layer may be improved.
However, since an optical distance between the optical cavity layers is set as an optimal distance when the organic light emitting display device including the optical cavity layer is viewed from a front side, a change in an interference length of light occurs when viewed from a side. As a result, as a viewing angle is changed, a decrease in luminance and a color shift as compared with a front side are caused, and as a result, many display characteristics deteriorate.